* Motegi, USTR Lighthizer to meet again on Thursday (Recasts throughout with quotes, details)

By Jonas Ekblom

WASHINGTON, Aug 21 (Reuters) - Japanese Economy Minister Toshimitsu Motegi said on Wednesday there were still gaps that needed to be filled before Tokyo and Washington could agree on a bilateral trade deal and that negotiations with his U.S. counterpart were "very tough."

Motegi is visiting Washington, D.C., for talks with U.S. Trade Representative Robert Lighthizer, where the two sides hope to narrow gaps on areas such as agriculture and automobiles in order to clinch an early bilateral deal.

"Issues that need to be sorted out in ministerial-level talks have been narrowed down quite a bit," Motegi told reporters after his meeting with Lighthizer.

"We agreed to speed up discussions and work on the remaining issues for an early achievement of results," he said.

The talks aims to lay the groundwork for a possible meeting between Japanese Prime Minister Shinzo Abe and U.S. President Donald Trump, to be held on the sidelines of this weekend's G7 summit in France.

Separate trade talks with China and Europe have made little headway and Trump is keen to clinch an early deal with Japan that would open up its politically sensitive agriculture sector, as well as curbing Japan's U.S.-bound auto exports.

Japan, on the other hand, wants the United States to cut tariffs on imports of car parts and industrial goods - something Washington is reluctant to do.

"Discussions are undoubtedly deepening. But there are still gaps that need to be filled," Motegi said when asked whether progress had been made toward an agreement at Wednesday's meeting.

Motegi said he and Lighthizer did not spend much time discussing a timetable on when a deal might be secured.

They will meet again on Thursday afternoon after working-level talks between the two sides, Motegi said. (Writing by Leika Kihara in TOKYO Editing by Shri Navaratnam and Paul Tait)